In such chopping arrangements, a stream of fodder is usually supplied via feed rollers to the rotating anchor plate of the drum which is provided with cutting blades normally arranged on a slant which chop the supplied fodder into small pieces with the counter blade fixed in the chopping arrangement. In order to allow for good chopping performance, it is necessary that the gap between the cutting blades and the counter blade has a constant value which is usually less than 1 mm; however, the gap between the cutting blades and the counter blade increases during the application of such a chopping arrangement due to the abrasion of the blades which comes about and their reduction due to regrinding, so that it is necessary to readjust the counter blade every now and then.
German Pat. No. 29 26 538 discloses an adjustable mounting for a counter blade which cooperates with the blade drum of a chopper. This mounting has a shifting element operated by an adjusting device for displacing the counter blade in the direction of feed towards the blade drum and which can be clamped together with the counter blade between clamping elements whose effective direction is aligned at right angles to the adjusting device of the counter blade. Between the adjusting device and the shifting element there is a lever pivoted around an axis parallel to the length of the counter blade, this lever, on the one hand, being acted upon by the adjusting device and, on the other hand, acting upon the shifting element so as to displace it in the direction of adjustment. The shifting element and the counter blade both remain clamped during adjustment between the clamping elements, whose clamping power is set to be smaller than the shifting power of the shifting elememt.
In this known adjustment arrangement, the clamping device and the adjusting device are thus independent of one another and must therefore be operated separately. Due to the adjusting lever used, a translational device to multiply its power is also required, so that the overall expenses are high.
Further, German Utility Model No. 71 43 407 discloses an adjustable mounting for the counter blade of a chopping arrangement, having a shifting element in the form of a concentric collar to displace the counter blade towards the blade drum, this collar being adjustable by means of a nut and the shifting element and the counter blade being capable of being clamped by means of a further screw which is clamped into the concentric collar by the nut. In order to release these screws for readjustment, parts of the machine housing must be removed, so that when the screws are released there is furthermore no more clamping effect for the counter blade.
The optimal functioning of the chopping arrangement thus requires that the distance between the blade and the counter blade be exactly maintained. Since each regrinding of the blades makes their path of rotation smaller, the counter blade must be readjusted until the blade gap has regained the proper width. If, as is usually the case, the counter blade attachment is designed in such a way that there is an adjusting screw and an attachment screw on each side, they must be tightened with a very high moment of torsion due to the high vibrating cutting forces and the great load on the attachment screws. Further, this is impeded in the case of conventional attachment arrangements by the poor accessibility resulting from the parts of the moving and driving gear surrounding the attachment area.
Furthermore, it is only possible to measure the blade gap accurately when the counter blade has reached its definitive posiion after all attachment screws have been tightened, so that it is necessary to repeat the troublesome adjustment process several times.